## Description
Adds automatic key failover for centralized OpenAI provider, covering both chat completions and responses APIs. Same shape as the Anthropic PR: each upstream call walks the configured key pool, keys are marked **temporary** on 429 (with cooldown from `Retry-After`) and **permanent** on 401/403. Each agentic-loop iteration gets its own fresh walker so a tool-call continuation can fail over independently of the initial request.
BYOK is unchanged: BYOK requests run as a single attempt with no failover.
## Changes
- `config.OpenAI` carries a `KeyPool`. `Key` remains for BYOK Authorization Bearer set per interception.
- Chat completions blocking interceptor: walks the pool via `newChatCompletionWithKeyFailover`, marks keys on key-specific failures, returns on first success or non-failover error.
- Chat completions streaming interceptor: per-iteration walker. Pre-stream failures fail over to the next key; mid-stream errors are relayed as SSE events.
- Responses blocking interceptor: extracts `newResponseWithKeyFailover` parallel to chatcompletions.
- Responses streaming interceptor: per-iteration walker, retains the existing buffer-then-forward design.
## Related Issues
Related to: https://github.com/coder/internal/issues/1446
Related to: https://linear.app/codercom/issue/AIGOV-197/aibridge-automatic-key-failover-for-bridged-and-passthrough-routes
## Follow-up PRs
- Bedrock multi-key support.
- Refactor provider vs interceptor config separation.
- Record the actually-used key in the interception credential hint after failover.
> [!NOTE]
> Initially generated by Claude Opus 4.7, modified and reviewed by @ssncferreira
This PR merges code from `coder/aibridge` repository into `coder/coder`.
It was split into 4 PRs for easier review but stacked PRs will need to
be merged into this PR so all checks pass.
* https://github.com/coder/coder/pull/24190 -> raw code copy (this PR,
before merging PRs on top of it, it was just 1 commit:
https://github.com/coder/coder/commit/70d33f33200c7e77df910957595715f81f9bec24)
* https://github.com/coder/coder/pull/24570 -> update imports in
`coder/coder` to use copied code
* https://github.com/coder/coder/pull/24586 -> linter fixes and CI
integration (also added README.md)
* https://github.com/coder/coder/pull/24571 -> added exclude to
scripts/check_emdash.sh check
Original PR message (before PR squash):
Moves coder/aibridge code into coder/coder repository.
Omitted files:
- `go.mod`, `go.sum`, `.gitignore`, `.github/workflows/ci.yml,`
`Makefile`, `LICENSE`, `README.md` (modified README.md is added later)
- `.github`, `example`, `buildinfo,` `scripts` directories
Simple verification script (will list omitted files)
```
tmp=$(mktemp -d)
echo "$tmp"
git clone --depth=1 https://github.com/coder/aibridge "$tmp/aibridge"
git clone --depth=1 --branch pb/aibridge-code-move https://github.com/coder/coder "$tmp/coder"
diff -rq --exclude=.git "$tmp/aibridge" "$tmp/coder/aibridge"
# rm -rf "$tmp"
```
Susana Ferreira